Quarterly Results of Operations (unaudited) - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Results of Operations (unaudited)
Inventory reserves	$ 200	$ 800	$ 300	$ 300	$ 600	$ 800
Restructuring charges	$ 300				$ 282	$ 18	$ 2,621
Variable compensation expense		800	$ 2,200
Stock-based compensation acceleration				1,100
Revenue for fully written down inventory		$ 1,500		$ 2,300